Recently, the surface profiles of nanostructures have been reduced in size in order to develop microfabrication
techniques, such as lithography and nanoimprinting. In particular, feature sizes of a few tens of nanometers are common
in the semiconductor industry. This study uses a Mueller matrix polarimeter, which is based on a scatterometry technique,
to evaluate the surface profiles of nanostructures. In this technique, a nanostructure profile is determined from the
Mueller matrix which expresses all the polarization properties of the sample by experimental measurements and
calculated values using rigorous coupled-wave analysis (RCWA). This technique is more useful than conventional
scatterometry based on ellipsometry since it is able to determine the total polarization properties of a sample. This is
because, the Mueller matrix is able to estimate the surface profile of a nanostructure to greater precision. The grating
period of a Cr/Cr2O3 structure on a SiO2 substrate was measured using a dual-rotating retarder polarimeter. The
experimental results agree well with the values obtained by numerical analysis. We measured the characteristic of non-diagonal
elements in the Mueller matrix by varying the incidence azimuth of the sample. We have demonstrated the
possibility of evaluating a nanostructure profile from the Mueller matrix.